Recently, natural energy such as sunlight power generation and wind power generation has been introduced in an active manner, and the natural energy has been utilized even by general customers by installation of a solar panel. A power generation apparatus using the natural energy depends on a meteorological phenomenon, weather, and the like, and thus there is a case where a power system may be unstable.
To solve instability relating to the power system, there is known a technology in which a storage battery is connected to the power system, and a variation in power generation due to natural energy and the like is compensated through output adjustment by charging or discharging of the storage battery. As this technology, for example, a load frequency control (LFC), in which output adjustment in accordance with the demand for electric power is known. In LFC, a raising command for instruction of an increase in an output, and a lowering command for instruction of a decrease in the output are transmitted to an electric power generator, thereby constantly maintaining a frequency of a system, and a link line power flow.
Typically, in LFC, the raising command and the lowering command are controlled to be entirely uniform. However, in the case of transmitting the command for output adjustment in LFC to the storage battery, even when the raising command and the lowering command are set to the same amount, the power storage residual amount of the storage battery decreases due to a charge and discharge loss in the storage battery, and thus, finally, it is difficult to cope with the raising command (discharge command for the storage battery). In addition, in contrast, even in a case where an amount of charge and an amount of discharge are set to the same as each other through the whole, a command value is inclined to a charge direction at a certain time zone, and thus charge is carried out to the capacity upper limit of the storage battery, and a chargeable electric power amount may be zero.
In this regard, in the related art, there is known a technology in which an operation range, which is a dynamic range of state of charge (SOC) for each storage battery, is limited, and charge and discharge of the storage battery are controlled in the operation range of SOC, or storage battery information including a charge performance and a battery residual amount of a plurality of storage batteries is acquired for a constant time interval, and the charge and discharge are controlled on the basis of the storage battery information.
However, in the related art, in a case simultaneously operating storage batteries in which operation ranges of SOC are different from each other, it is necessary to examine a process or a rule in accordance with the respective operation ranges, and thus application to a system, in which a large number of storage batteries are necessary, is difficult, and thus inefficient operation may be carried out.